Some days I go to work, and I can smile at people. We exchange pleasantries and stale jokes in the coffee room.

It is easy to forget that none of them want what's best for me. NONE of them.

In a perfect world, we would all work together towards improved efficiency, lowering costs and bettering service.

This is not that world. Everyone has to watch out for their own interests.

And that's not such a bad thing. Who is the one most qualified to watch out for your own interests than you? really, the scheme is an excellent division of labor.
In the system, NOT looking out for your own interests would really be letting your employer down.

A book that I picked up at a trade show after a cranky and frustrating morning at work reminds me of my duty to look out for number one.

What Would Machiavelli Do? the Ends Justify the Meanness

It's pretty silly, but sometimes I have to remember that I am not among friends. I am among co-workers.